This Core measures serum and urine chemistries and calculates urine supersaturations (SS) for human (Projects 1,2 and 4), and rat protocols (Project 3), and prepares dialyzed urine proteins and pure urine proteins (Project 1, 2 and 3). The core also performs assays to measure crystal growth, aggregation, nucleation, upper limit of metastability and crystal: cell adhesion (Project 1, 2 and 3).